Field of the Invention
The present invention relates to an imaging-optical system, a stereo camera apparatus, and an in-vehicle camera apparatus.
Description of the Related Art
Recently, various types of imaging apparatuses have been put into practical use, including not only a camera device for photographing but also an in-vehicle camera apparatus, a stereo camera apparatus, and a monitoring camera apparatus (refer to Patent Documents 1 to 5).    Patent Document 1: Japanese Patent Application Laid-Open Publication No. 2012-123122    Patent Document 2: Japanese Patent Application Laid-Open Publication No. H01-134411    Patent Document 3: Japanese Patent Application Laid-Open Publication No. 2010-072051    Patent Document 4: Japanese Patent Application Laid-Open Publication No. 2009-069369    Patent Document 5: Japanese Patent Application Laid-Open Publication No. 2012-220741
Generally, an imaging-optical system mounted on many types of imaging apparatuses is required to have a miniature body, a certain level of wide angle of view, and brightness with a better performance.
Obviously, it is preferable that various types of aberrations be corrected adequately when considering performance.
Generally, when the number of lenses configuring the imaging-optical system increases, parameter of the aberration correction also increases, and the aberration correction can be therefore performed successfully. However, the increase of the number of lenses causes an increase in the length of the imaging optical system.